The invention concerns a down hill ski boot. More particularly, the invention relates to a down hill ski boot having a configuration which combines comfort with secure attachment to a ski binding.
The first ski boots, in leather, were relatively supple. They offered good comfort and permitted an easy stride, thanks to the suppleness of their sole. Finally, to assure the good transmission of force between the foot and the ski, that is to say to reduce the capacity of deformation of the boot, the sole and the upper have become more and more rigid, and the stride, as a consequence, less and less easy. With the appearance of boots in plastic materials, the upper, but more particularly the sole, has acquired a rigidity which assures an excellent interface between the foot and the ski by the intermediary of the ski binding, but yielding a normal stride difficult by reason of the total lack of flexibility of the sole at the level of the metatarsal joint.
For a certain number of years, ways of facilitating the stride with the plastic ski boots by various means were sought. In European Patent No. 0 664 969, the content of which is incorporated by reference, a means is proposed of providing a supple zone forming a hinge in the metratorsal zone of the rigid sole and to divide the shell of the boot into two articulating parts at the level of the said joint, the two parts being among other things, connected by a device permitting locking of the joint.
A boot constructed according to the same principal and which also known is U.S. Pat. No. 5, 572, 806, the content of which is incorporated by reference. This boot differs from the preceding in that the locking device is slidingly mounted within the thickness of the sole. Such boots do not provide a real suppleness permitting a natural operation of the foot during walking. On the other hand, in that it concerns walking, these boots are heavy and of little comfort.
Another approach to the problem, putting to the side the stopgap solutions mentioned above, is described in French patent 2 130 644, the content of which is incorporated by reference. It consists of a sort of auxiliary box in which one encloses the boot to the upper and supple sole.
The boots designed for cross-country skiing certainly have a suppleness at the level of the metatarsal zone in a manner to permit an operation of the foot with a minimum of resistance. These boots are not in all cases fixed in the front and are of a type that the sole cannot have a longitudinal rigidity to the front stop and the heel piece, as is the case with the soles of ski boots in a conventional ski binding, soles which must be sufficiently rigid for supporting the longitudinal thrust applied by the binding and the vertical thrust applied by the brake pedal.
Today, persons practicing leisure skiing would like to find on the market a light and comfortable boot permitting, on the one hand, an easy stride and skiing in good conditions while at the same time, fixing the boot to a ski by means of a binding of the conventional type.